Key Eligibility

Subjects must have histologically confirmed invasive breast cancer and registration must occur within 12 months after the first histologic diagnosis of invasive breast cancer. Her-2 negative, defined as: ◦In-situ hybridization (ISH) ratio of < 2.0 (if performed)◦Immunohistochemistry (IHC) staining of 0-2+ (if performed)◦Deemed to not be a candidate for Her-2 directed therapyEligible TNM Stages include: ◦Estrogen receptor (ER) and Progesterone receptor (PR) negative (defined as <1% staining for ER and PR by IHC): T2 or T3 N0, T0-3N1-3◦ER and/or PR positive (defined as ≥ 1% staining for ER and/or PR on IHC): T0-3N1-3 or T3N0.◦The eligibility of neo-adjuvant subjects is assessed on the basis of cTNM. The same eligible TNM combinations apply.No history of invasive breast cancer in 5 years prior to study registration other than the current diagnosis (prior ductal breast carcinoma in situ [DCIS] at any time is acceptable). 1.5 Patients must have had a bilateral mammogram within 12 months prior to registration, unless the initial surgery was a total mastectomy, in which case only a mammogram of the remaining breast is requiredPrior Treatment 2.1 All adjuvant or neoadjuvant chemotherapy (at the discretion of the treating physician) and surgery completed at least 21 days prior to registration. Concomitant radiation, biologic therapy, hormonal therapy, and bisphosphonates are acceptable. 2.2 Surgical margins must be clear of invasive carcinoma. If there is microscopic residual ductal in situ disease present at lumpectomy or total mastectomy margins, further excision is highly recommended. If further excision is not undertaken, the subject may still be entered on study, provided that in addition to breast or chest wall irradiation, a boost to the tumor bed is delivered. In situ lobular disease at the margin is acceptable. 2.3 All subjects (both adjuvant and neo-adjuvant) must have sentinel lymph node biopsy and/or axillary lymph node dissection. Sentinel lymph node biopsy alone is allowed in the following instances: ◦Sentinel lymph node biopsy is negative: pN0◦Sentinel lymph node biopsy is positive for isolated tumor cells only:pN0 (i+) ◦Clinically node negative, T1-2 tumors with sentinel lymph node biopsy positive in < 2 lymph nodes without matted nodes and undergoing breast conserving surgery and tangential whole breast irradiation, or undergoing mastectomy and chest wall irradiation. ◾All women who undergo breast conserving therapy must receive concomitant radiotherapy. Radiation after mastectomy is to be administered according to pre-specified institutional guidelines. Radiation can be administered either prior to or during protocol treatment.◾Patients with hormone receptor positive breast cancer as defined above must receive at least 5 years of adjuvant hormonal therapy in the form of tamoxifen or an aromatase inhibitor, alone or in combination with ovarian suppression. (NOTE: for patients with ER and PR staining in less than 5% of cells, hormonal therapy for at least 5 years is strongly recommended but not required). Hormonal therapy can be initiated prior to or during protocol therapy.Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1

Comorbid Conditions 6.1 No history of other malignancy within the past 4 years, except for malignancies with a >95% likelihood of cure (e.g. non-melanoma skin cancer, papillary thyroid cancer, in situ cervical cancer). 6.2 No diabetes mellitus currently treated with insulin or sulfonylureas. 6.3 No history of serious digestive and/or absorptive problems, including inflammatory bowel disease and chronic diarrhea that preclude adherence to the study diet. 6.4 No history of severe cardiovascular, respiratory or musculoskeletal disease or joint problems that preclude moderate physical activity. Examples would include unstable angina, recent myocardial infarction, oxygen-dependent pulmonary disease, and osteoarthritis requiring imminent joint replacement. Moderate arthritis that does not preclude physical activity is not a reason for ineligibility. 6.5 No prior bariatric surgery or planning to undergo this procedure within the next 2 years after study registration. 6.6 No comorbid conditions that would cause life expectancy of less than 5 years. 6.7 No history of psychiatric disorders that would preclude participation in the study intervention (e.g. untreated major depression or psychosis, substance abuse, severe personality disorder) or prevent the patient from giving informed consent.BMI ≥27 kg/m2 documented within 56 days prior to study registration.Self-reported ability to walk at least 2 blocks